After watching the video on TVNZ's Breakfast show, Key associated it with Internet Party founder Dotcom.

The Internet-Mana Party has denied any involvement with the stunt, and lodged a complaint with TVNZ over the interview.

Key said he had drawn a "natural conclusion" when young people in the effigy-burning video were chanting the same thing as students at an Internet-Mana Party event. However, he was happy to accept he had been wrong.

"But in principle I only drew that conclusion because Internet-Mana, Dotcom's party, actually put up a video under their own banner and marketed it to people to go and see, so that was the reason I drew that logical conclusion," he said.

Key referred to a video of Dotcom onstage at a Christchurch event for the Internet-Mana Party, where a crowd of young people chanted "F... John Key". The footage was promoted by Internet-Mana.

"The picture of my face that was burnt as part of the effigy looked extremely similar to the one I saw in the previous Dotcom video," Key said.

"They [the people in the effigy-burning video] chanted exactly the same things.

"I think the Television New Zealand host, Rawdon [Christie] drew ... a similar sort of conclusion, certainly they didn't point out to me that it was different."

Internet Party leader Laila Harre was invited onto the Breakfast show and given a right to respond to Key's comments this morning.

Harre said the party neither created nor promoted the video in which an effigy of Key was burnt.

She was "quite cross" about the way TVNZ had handled the interview with Key yesterday, she said.

"You knew from your research, or should have known from your research, it had no relationship with the Internet Party," Harre said.

"You allowed the prime minister to lie and to cast a slur on the Internet-Mana Party in your conversation with him yesterday."

Christie said that in light of an earlier video posted online by the Internet Party, Key had the right to comment on the wider issue of negative politics taking place in the lead-up to the election.

A TVNZ spokeswoman said the broadcaster had received a complaint from the Internet-Mana Party about the interview, but it would not apologise for it.

"Immediately before we aired the video yesterday our presenter clearly stated that it had been sourced from [blog] Whale Oil," the spokeswoman said.

"He did not make any connection between the video and Kim Dotcom or the Internet-Mana Party. It was the [prime minister] who made this association."

Labour leader David Cunliffe called the effigy burning "appalling" and said he had no tolerance for it.